Abstract: A method for detecting defects with a surface ultrasonic wave in which a surface ultrasonic wave probe is brought into contact with a surface of a rotating cylindrical member via a thin film of a contact liquid medium such that a contact trace of the probe extends linearly or helically about the circumference of the cylindrical member. An ultrasonic wave propagates in the surface portion of the cylindrical member from the probe in an opposite direction to the rotational direction of the cylindrical member. The probe is provided in a front portion thereof with a projection slightly extending downward from a lower surface of the probe so that the thin film of the contact liquid medium is stably formed. There is substantially no thin film of the contact liquid medium on the surface portion of the cylindrical member in which the surface ultrasonic wave propagates.

Abstract: Columns, walls and other solid structures of concrete, wood, masonry or other materials are non-destructively tested by acoustic signals transmitted from a carriage. The carriage has a frame which is wheel mounted to move over the surface of the test candidate. An internally-mounted piezoelectric crystal roller as an acoustic signal generator or receiver is suspended from the carriage with two degrees of spring freedom to allow accommodation of irregularities in the test candidate surface. The assembly including the piezoelectric crystal roller and its flexible mounting are configured as a replaceable module relative to the carriage frame. The same carriage is useable as an echo type acoustic scanner or, in combination with other devices or carriages, as either an acoustic transmitter or receiver although inclusion of elements to perform both functions within the same carriage is contemplated.

Abstract: An ultrasonic sensor for use in an ultrasonic micro spectrometer includes a concave surface transducer having a concave ultrasonic wave transmitting/receiving surface and a plane transducer having a plane transmitting/receiving surface. The concave surface transducer is capable of transmitting converging ultrasonic waves toward a specimen, wherein the waves are reflected from the surface of the specimen and are received by the plane transducer which outputs electric signals corresponding to the intensity of the reflected ultrasonic waves. Based on a signal output from the ultrasonic sensor, a digital oscilloscope and FFT analyzer forms a distribution of spectral intensity indicating the intensity of the reflected wave as a function of frequency. The digital oscilloscope and FFT analyzer further forms a distribution of spectral phase indicating the spectral phase of the reflected waves as a function of frequency.

Abstract: A system and method for dynamically and non-destructively measuring the longitudinal stresses in a rail of a continuous rail track includes an ultrasonic transmitter which transmits a signature coded pulse pattern through a rail which pulse pattern is altered by the rail section dependent upon the longitudinal stress within the rail. The altered pulse pattern is then received and a data processor, in conjunction with a rail height detector, a rail temperature detector, and a rail splice detector, dynamically determines the longitudinal stresses in the rail as a function of the received pulse characteristics and calculates the stress free temperature (SFT) of the rail. A rail marker marks portions of the rail having unacceptable SFT values. Stress and related rail data are recorded on a data log. A position sensor provides milepost positions to three decimal places.

Abstract: A two probe time-of-flight system has a transmit probe emitting a diverging beam into a test material at a certain beam-center angle, and a receive probe with its main beam extending into the test material at that same angle, with the two probes being arranged symmetrical about a centerline normal to the test face. The transmit probe generates a pulse wherein a portion of the pulse reflects at the incident angle back to the receive probe, which detects the reflections and marks the reception time as a reference. A sampling unit captures subsequent echo energy returning from a region within the test material. The sampled energy above a given threshold is processed to identify the sample times relative to the marked reference time. The identified sample times are used to determine the depth that the echo energy originated from. Consecutive identified samples in the depth direction are used to detect the height of a flaw within the test material.

Abstract: The wheel rests upon a rail. A chassis mounted on a lifting and supporting mechanism carries slides arranged on either side of the rail and parallel to the rail. Two carriages are mounted to move translationally on the slides. Grinding devices, an ultrasound checking device and two position detectors are mounted on the carriages to move translationally in a direction perpendicular to the slides. The propagation time for the ultrasound in the rim is measured in two perpendicular directions and the width of the rim is measured. The propagation speeds of the ultrasound are calculated and compared so as to determine the stressed state of the rim.

Abstract: An apparatus for measuring the thickness of a clad material having an outer mother metal and an inner clad metal. The apparatus includes a transmitter crystal and a receiver crystal of a double crystal angle-type probe which contact the outer surface of the mother metal, for receiving a first echo from the boundary surface of the mother metal and clad metal, and for receiving a second echo from the inner, bottom surface of the clad metal. The apparatus further includes an amplifier for amplifying the echo signals, a detector for detecting the zero-crossing points of the echoes, a zero point determining circuit, a calculator for calculating the periods from a zero point in time to the zero-crossing points, and a calculator for calculating the thickness of the clad material and clad metal based on the calculated periods.

Abstract: A system and method for dynamically and non-destructively measuring the longitudinal stresses in a rail of a continuous rail track includes an ultrasonic transmitter which transmits coded focused shear pulses through a rail which are subsequently received by a linear array of sensors. A displacer adjusts the separation between the transmitter and the sensors to maximize the signal intensity received by a centrally located one of the sensors. A data processor, in conjunction with a rail height detector, a rail temperature detector, and a rail splice detector, dynamically determines the longitudinal stresses in the rail as a function of the velocity of propagation of the pulses, the stress free temperature (SFT) of the rail, and activates a rail marker to mark portions of the rail having unacceptable longitudinal stresses. Stress and related data is recorded on a data log. A video camera provides observed rail separation data to the data processor.

Abstract: A remote sensing system is provided which operates as a bipolarized, differential mode, LDI (laser differential interferometry) system to detect an electrical signal produced at a remote location. The system is adapted to reduce the effects of turbulence induced frequency fluctuations by using an array retroreflector apparatus which converts a single sensing beam into a single return beam having two, overlapping, transversely polarized sensing signals; thus, turbulence induced noise will be common mode to both return signals and cancel at the receiver.In preferred embodiments, the system is used to remotely detect an amplified array signal from a plurality of seismic detectors (e.g., geophones or hydrophones) connected to form an array at the remote location. The target is coupled to common motions at the selected location and the amplified array signal is coupled to an optical component within the target.

Abstract: A non-destructive, non-invasive arrangement is provided for detecting defects, such as voids, or poorly adhering layers in solid objects and laminated materials. A sensing signal is emitted by one transducer and received by two others. All of the sensors are disposed in a housing unit. The difference between the received signals is used to indicate a defect in the work piece proximate one of the transducers.

Abstract: A method of ultrasonic inspection of a reactor nozzle involves positioning emitter and receiver transducers on the exterior vessel wall near the nozzle. The emitter transducer is positioned and oriented so that it generates both primary longitudinal and transverse beams. The primary longitudinal beam is directed at the inner radius of the nozzle. The transverse beam is directed toward the interior vessel wall at an angle of about 30.degree. to the normal. Most of the energy of the transverse beam is converted to a secondary longitudinal beam also directed toward the inner radius of the nozzle. The receiver transducer is positioned on the exterior vessel wall about 4" from the emitter transducer so as to be able to detect reflections of both the primary and second longitudinal beams from any potential defect in the nozzle volume adjacent the inner radius.

Abstract: Various ultrasonic transducer assemblies are disclosed in which each assembly includes a pair of ultrasonic transducers for emitting or receiving an ultrasonic wave, respectively, and wherein the ultrasonic transducers include a concave shaped ultrasonic transducer and a flat shaped ultrasonic transducer. The ultrasonic transducer assemblies realize excellent magnitude of accuracy, resolving power, versatility and simplicity in handling. In addition, various ultrasonic acoustic microscopes are disclosed incorporating the aforementioned ultrasonic transducer assemblies and realizing the same results thereof.

Abstract: A quality assurance inspection system utilizes a plurality of ultrasonic transducers to probe an elongated tube for both dimensional and structural integrity. The transducers are pulsed in rapid succession, and echo signals are conducted over separate RF channels and through a multiplexor to a lesser number of detector signals channels, each including a discriminator. Inspection windows are opened in these discriminators to permit detection of echo signals and the generation of time mark signals for stopping a plurality of clocks which then register pulse-echo time intervals. These data are computer processed to provide tube dimension and flaw information.

Abstract: A device is disclosed for measuring the variation of the distance separating the two faces of a layer of solid material by means of ultrasounds, comprising:a generator generating a first alternating electric signal,an electroacoustic transmitting transducer,first coupling means for applying the ultrasonic wave to said layer of material,an electroacoustic receiving transducer,second coupling means for applying said ultrasonic wave to said electroacoustic receiving transducer,means for continuously measuring the variation of the phase-shift of the electric signal emitted by the receiving transducer with respect to said first alternating electric signal, andcomputing means for deriving said distance variation from said phase-shift variation, wherein:said electroacoustic transmitting and receiving transducer, as well as said first and second coupling means are disposed on the same side of said layer of material, andsaid first and second coupling means are solid ultrasonic wave-guides.

Abstract: Pipe inspection apparatus comprising transducers for transmitting pulsed beams of ultrasonic energy longitudinally, transversely and obliquely into the wall of the pipe for detection of flaws. The apparatus includes a motor driven chuck 18 for rotating the transducers about the a pipe P and motor driven roller 12 for axial movement of the pipe whereby the transducers move in a helical scanning path. A control system 60 maintains the axes of the pipe and circle array of transducers in coincidence and with hydraulic controls 80 maintains each transducer at fixed distance to the pipe for sonically coupling thereto by a flowing liquid whereby a shear wave is generated by each beam in the tubular wall. The transducers comprise multiple pairs, the members of which are diametrically opposed and transmit in opposite directions, for transmitting longitudinally at angles of 12.degree., 27.degree. and 42.degree.

Abstract: An automatic, ultrasonic system for controlling the filling of different sizes of beverage container which may or may not contain various quantities of ice. The system includes a housing, a front and a rear pair of separate transmitter and receiver crystals mounted in the housing with a lens on the lower surface of each crystal. Each crystal is located within a separate non-ferrous metal tube. Polyurethane foam fills the space within the housing and the tubes.

Abstract: A three-dimensional imaging system for obtaining a three-dimensional image of an object being scanned ultrasonically comprises a source arrangement for sequentially transmitting ultrasonic energy toward the object in successive directions in a first scanning plane, followed by sequential transmission of ultrasonic energy toward the object in successive directions in successive scanning planes parallel to the first scanning plane, a detector arrangement for receiving reflected energy and converting the reflected energy to electrical signals, and a processor for processing the electrical signals to develop reconstructed image data of the object, the reconstructed image data comprising forward projections of the object into a left image plane and a right image plane to form left and right images, respectively, the left and right images forming a stereo pair for composite display by a display unit.

Abstract: A system and method for measuring the acoustically induced vibrations within a living organism. The object is ensonified to set it into low frequency vibration. A continuous wave beam of ultrasonic energy is transmitted along one path and focused at the tissue to be investigated. A focused transducer receives the reflected beam along a second axis such that the intersection of the transmitted and received beams define a small, concentrated region positioned at the object under investigation. The received beam is phase modulated by the amplitude of vibration of the object producing sidebands whose amplitude can be ratioed to the amplitude of the high frequency peak to determine the absolute amplitude of the low frequency vibration.

Abstract: A method and device of scanning objects by means of ultrasound echography by repeated transmission of ultrasound signals and the reception of the ultrasound echoes includes the following operations:(a) storing an echographic line in a memory;(b) determining the ratio of the power spectra for two distinct observation depths, including correction for the effects of the diffraction;(c) storing in a memory and/or displaying the frequency-dependency of the scatter function of the object examined;(d) repeating the proceding operations for two other observation depths which correspond to resepctive boundaries of homogeneous zones, and for other echographic lines.

Abstract: An automatic, ultrasonic system for controlling the filling of different sizes of beverage containers which may or may not contain various quantities of ice. The system includes a transducer assembly and a control module, both preferably connected to a beverage dispenser valve assembly. The transducer assembly includes a pair of piezo-electric crystals for separately transmitting and receiving ultrasonic wave energy from the grate, the cup lip, the top of any ice in the cup, and the rising liquid level. The control module includes a microcomputer and associated circuitry.

Abstract: A three-dimensional imaging system for obtaining a three-dimensional image of an object being scanned ultrasonically comprises a source arrangement for sequentially transmitting ultrasonic energy toward the object in successive directions in a first scanning plane, followed by sequential transmission of ultrasonic energy toward the object in successive directions in successive scanning planes parallel to the first scanning plane, a detector arrangement for receiving reflected energy and converting the reflected energy to electrical signals, and a processor for processing the electrical signals to develop reconstructed image data of the object, the reconstructed image data comprising forward projections of the object into a left image plane and a right image plane to form left and right images, respectively, the left and right images forming a stereo pair for composite display by a display unit.

Abstract: An ultrasonic apparatus and method for testing a material comprises an oscillator which generates a selected frequency in the ultrasonic range. A transducer is connected to the oscillator for applying an ultrasonic signal to the material and for receiving an echo signal back from the material. Two phase detectors are utilized one of which receives the echo signal and an in-phase oscillator signal to generate a first display signal, and the other of which receives a quadrature signal which is 90.degree. out of phase from the oscillator signal, as well as the echo signal to generate a second display signal. The first and second display signals are utilized in a visual display such as a cathode ray tube, to generate an image. The image changes according to the phase shift between the ultrasonic signal transmitted into the material and the echo signal, which, in turn, can be utilized to determine the presence and depth of a flaw or boundary in the material.

Abstract: Sound velocity along a straight segment is estimated by measuring ultrasound pulse travel time as ultrasound pulses are directed along the straight segment from successively different transmitting or receiving positions. A sequence of data pairs comprising travel times and distances traveled is measured and plotted on a graph. Estimated sound velocity is derived from the slope of affine equation fitted to the plotted points.

Abstract: An non-destructive testing method employs an ultrasound generator which provides a beam having an axis which intersects the outer surface of an object to be tested at an angle relative to a line normal to the surface which is in the range of 23.degree. to 28.degree.. A longitudinal mode wave and a shear mode wave are propogated within the object and the shear wave is converted into longitudinal mode waves by reflection from an opposite surface of the object. The propogated and mode converted waves are reflected from different portions of a defect and the echos arrive serially in time at a receiver transducer. The ultrasound generator and receiver transducer are sonically isolated. The received signals have a favorable signal-to-noise ratio and the times of receipt thereof are employed to determine the dimensions of a detected defect.

Abstract: Method and apparatus for detecting the distance between an ultrasonic objective and an object to be imaged in order to prevent contact between the two. For this purpose, light rays, after entering into an immersion means (water) between the objective and the object, being reflected by the object, and emanating from the immersion means are fed through the ultrasonic objective to a photo-receiver and converted into electric signals. The front face of the lens body of the ultrasonic objective is provided with an opaque ring zone. This arrangement makes it possible simultaneously to illuminate the object.

Abstract: The ultrasonic pulse-echo method for locating and characterizing flaws in a partly submerged metal structure utilizes a device comprising an acoustic antenna (3), means (18) for preprocessing the echo signals, data transmission means (23-23') and a central processing unit (6).

Abstract: A two-probe ultrasonic flaw detection apparatus, in which an ultrasonic wave is transmitted from a transmission probe into an object being inspected and ultrasonic waves reflected from a reflection surface in the object are received by a reception probe, operates to determine the position at which the combined intensity of ultrasonic waves reflected from each part of the reflection surface form a maximum. The reception probe is then moved to the position of maximum reception intensity. The position of maximum reception intensity is determined using as input parameters the ultrasonic characteristics of the object being inspected and of the transmission and reception probes, and the position of the transmission probe and the angle of incidence of the ultrasonic wave into the object.

Abstract: Ultrasonic testing methods and units for characterizing planar flaws in hard-to-inspect materials such as welded and cladded pipes containing intergranular stress corrosion cracks. The invention characterizes flaws with pitch-catch transducers positioned front to back on a single module. One module uses a bimodal transducer to transmit longitudinal and shear waves to produce, through surface wave mode conversion, reflection and diffraction, a triplet of associated longitudinal and shear wave signals received by another bimodal transducer. Other modules use pitch-catch transducers to produce a doublet of associated shear wave signals from diffraction of an incident longitudinal and/or shear waves at the upper and lower extremities of underclad fatigue cracks and buried cracks. The signals are enchanced by multiple one sided cross focusing on preselected target areas in the test specimen and are cognizable by pattern recognition.

Abstract: A non-destructive method and apparatus for inspecting materials in excess of 500.degree. C. includes a dual transducer disposed upon a delay line suitable for operation at the elevated temperatures. The delay line is divided into two parts acoustically isolated and is cooled by a fluid to maintain the surface upon which the transducers are mounted at a safe operating temperature.

Abstract: An ultrasonic sensor for determining objects in air or other gaseous media is disclosed. The sensor comprises a first ultrasonic transducer having a piezoelectric transmitter. A reflector is provided having a concave surface facing the first ultrasonic transducer which forms a segment of an ellipsoid. The reflector has two focal points, the first of which is closer to the reflector and the second of which is near the object to be detected. Between the first ultrasonic transducer and the reflector, a second ultrasonic transducer is provided which is arranged at the first focal point of the reflector. Preferably, the surface of the second ultrasonic transducer facing the reflector forms a spherical segment. By this arrangement, an increase of the receiving aperture is achieved, and objects can be determined which have a normal to the reflection surface inclined with respect to the axis of the sound lobe by an object position angle which is substantially larger than .+-.3.degree..

Abstract: A method and apparatus for ultrasound tomography for use in clinical diagnostics, the apparatus comprising paired couples of transmission transducers (3) and reflection transducers (5,6), the paired couples of transducer means being independently operable within a container (1) of ultrasound transmission medium to provide data capable of processing by computational methods for mathematical reconstruction of the distribution of specific values of acoustic data to permit separate comparative and synergistic examinations of the data thus obtained to classify the internal structure of a body.

Abstract: An ultrasonic imaging device includes a transducer assembly for transmitting ultrasound pulses into a portion of a structure to be imaged and receiving ultrasound scattered by said structure portion and generating signals in response thereto, means to energize said transducer assembly to transmit said pulses, scanning means for progressively relating said transducer assembly to successive portions of said structure according to a scanning pattern, and receiver and signal processing means for assembling an image from said generated signals, the transducer assembly comprising separate transmitting and receiving transducers, one of said transducers being a simulated conical transducer having a line focus, and the other of said transducers having its axis in parallel alignment with said line focus, the scanning means being operative to move said line focus in relation to a structure to be imaged in accordance with said scanning pattern.

Abstract: Beams of ultrasound are transmitted into a rail. The transmission alternates between vertical and oblique beams. Transmission of the beams and reception of ultrasonic echoes is accomplished by a probe which includes a two channel ultrasonic transducer. The echoes are displayed simultaneously on two linear arrays of LED's which are arranged to resemble the relationship between a vertical beam and an oblique beam.

Abstract: A process and a device for the nondestructive ultrasonic testing of the material of generator rotor teeth providing with an inserted slot wedge, using a probe arrangement including transmit probes, reference probes and defect detection probes which are disposed on a support plate in such a manner as to be movably attached to the teeth, wherein ultrasonic beams are transmitted and reflected by the rotor teeth flanks and the reflected beams are received in a reference probe utilizing a two-fold deflection of the sound at the tooth flanks which are inclined with respect to the tooth back. An ultrasonic beam, reflected by any existing defects of a given type and orientation, is selectively received outside the receiving range of the normally reflected acoustic beam by means of a defect detection probe, and the damaged locations is detected by comparison of the ultrasonic signals received by the reference and defect detection probes.

Abstract: A bidimensional imaging system by echoes including a transmitting array and a receiving array. The transmitting array includes a row of transmitters (E.sub.1, E.sub.2, . . . , E.sub.i, E.sub.N) parallel to a direction Oz and the receiving array includes a row of receivers in a direction Ox. All the transmitters simultaneously transmit signals with different codes. The signals received are demodulated and the real and imaginary components of these signals are applied to two multiplexing circuits (61.1, 61.2). After modulation the multiplexed signals are applied to a Fourier transformation circuit (63), which sequentially supplies reception channels V.sub.k (.theta..sub.k) for the direction referenced by angle .theta..sub.k and which are stored in memories (66.1, 66.2). Other memories (70.1, 70.2) contain signals S.sub.i (.phi..sub.i) transmitted in an angular direction referenced by .phi..sub.i. The two pairs of memories (66.1, 66.2 and 70.1, 70.

Abstract: A programmable ultrasonic thickness and acoustic velocity measuring instrument is provided which includes automatic zeroing (calibrating) means, automatic temperature compensation and high temperature warning means, automatic probe identification means, means for automatically correcting the measurement readings for probe characteristics, means for storing and displaying of the minimum wall thickness during a predetermined time interval, and means for providing a display indicative of the difference between a measured thickness and a preprogrammed value.

Abstract: A novel method for imaging body tissues is disclosed wherein an ultrasonic pulse having a radially asymmetric side-lobe pattern surrounding a central focal lobe is generated. A receiver for receiving echoes of this pulse is provided which exhibits a sensitivity to echoes from the aforementioned side-lobe pattern which is relatively decreased by comparison to its sensitivity to echoes from the central focal lobe. In the preferred embodiment, square transducers which are rotated with respect to the focal axis by about 45.degree. are used to practice the disclosed method.

Abstract: An ultrasonic inspection apparatus for inspecting a test piece includes an ultrasonic transducer for transmitting test signals into the test piece, for receiving associated response signals reflected back thereto, and for generating a defect signal when a response signal indicates an abnormal condition in the test piece. A control signal generator generates a control signal at predetermined intervals of distance of movement of the transducer relative to the test piece while the transducer generates test signals at a frequency independent the control signal frequency. A principal counter counts the control signals and generates an alarm signal when its count exceeds a value indicating that sufficient defect signals have been generated during movement of the transducer over a predetermined distance to confirm the presence of an unacceptable abnormal condition.

Abstract: Two ultrasonic wave beams of different frequencies are emitted into a body under consideration from different locations on a surface of the body and a scattered wave beam created at a scattering point in the body by the interaction between the two ultrasonic wave beams is received. The emitting locations of the ultrasonic wave beams and the receiving location of the scattered wave beam are caused to scan. Thus, the stress distribution in the body is measured on the basis of the received outputs resulting from the scanning.

Abstract: An improvement to ultrasonic probes useful in the non-destructive testing of structural materials includes a compact, high-sensitivity coaxial design probe. The probe has a centrally located transmitter point and a circumferentially arranged receiver ring. The geometrical relationship between the transmitter point and the receiver ring provides for high-sensitivity in the detection of defects and allows for a compact construction without orientational sensitivity. A receiver tube is provided which encloses the probe and acts as a tuned wave guide for the detection of ultrasonic vibrations from the structural material under test. The increased sensitivity of the improved ultrasonic probe is advantageous in the testing of non-metallic structural materials having a complex composite structure. The compactness of the improved ultrasonic probe is advantageous in the testing of structural materials having complex and narrow shapes.

Abstract: Methods and apparatus for calibrating terminated ultrasonic electroacoustic transducers are disclosed. The transducers are excited by a driving signal to emit an ultrasonic acoustic wave, which wave is received either by the same transducer after reflection or by a second transducer to produce an output signal. The driving signal and output signal are supplied to measuring circuitry deriving transdBACKGROUND OF THE INVENTIONThe invention described herein was made in the course of work under a grant or award from the Department of Health, Education and Welfare.

Abstract: An ultrasonic image of improved resolution is obtained by utilizing separate transducers for transmission and reception of ultrasonic pulses utilized for imaging, one transducer being a cylindrical or simulated cylindrical transducer having a line focus and the other transducer being aimed along the focus of the first transducer. An area to be imaged may be scanned by rotating and/or traversing the transducers as a unit.

Abstract: Apparatus for coupling an ultrasonic energy transducer to a target object, such as a human patient, through an energy transmitting liquid. The coupling apparatus comprises an open top container for holding the energy transmitting liquid. The transducer extends through the open container top for immersion below the surface of the liquid and for selective movement relative to the container. A support member is provided for holding the container in contact with the patient. The support member has a ring for rotatably receiving and supporting the container. The ultrasonic wave output from the transducer may be directed to different portions of the patient by selective rotation of the container and/or by repositioning the transducer within the container.

Abstract: A scanning mechanism for oscillating a watercoupled ultrasonic transducer, over the surface of a part containing a strip weld and, positioning the ultrasonic transducer along orthogonal paths of travel (one parallel to and the other orthogonal to the strip weld) is disclosed. Position sensors forming part of the scanning mechanism continuously provide signals relating to the orthogonal and oscillatory position of the transducer. An ultrasonic beam emitted by the transducer enters the part and is reflected back and forth between the surfaces of the part, through the weld. Ultrasonic specular reflections (flaw echoes) created by flaws or faults in the weld travel back to the transducer.

Abstract: A device for ultrasonic examination, comprising a flat mosaic of a row of transmission transducers and a number of rows of receive transducers which are symmetrically arranged with respect thereto. The device furthermore comprises means for applying actuation pulses to one transmission transducer at a time, and means for enabling receive transducers in the time interval following each actuation pulse, and for at the same time displaying on an image display device an image of a section of the examined body in a plane perpendicular to the plane of the mosaic and through the line of transmission transducers.

Abstract: A method of non-destructively testing materials comprises directing an incident beam of ultrasonic waves onto the surface of a material and detecting the beam reflected by the surface, the angle of incidence and the wavelength of the ultrasonic waves being detected, and the critical angle of incidence at which the energy of the reflected beam passes through a minimum being determined for at least two different wavelengths. A curve is then prepared showing how the critical angle or a quantity dependent thereon varies with the wavelength or a quantity dependent thereon. Apparatus for carrying out the method comprises a goniometer for transmitting the incident ultrasonic beam and detecting the reflected beam, means for varying the angle of incidence of the beam, means for varying the wavelength of the waves, and means for determining the critical angles of incidence. The invention is applicable inter alia to the testing of tempered steel components.

Abstract: In an ultrasonic pulse-echo test circuit a probe means is coupled via a liquid filled coupling path to a workpiece which undergoes motion relative to the probe means. For each search signal transmitted by the probe means the transit time of such signal is measured from the time of transmission by the probe means to the receipt of the workpiece rear surface responsive echo signal. A computer coupled to receive the transit time values is programmed to classify transit time changes as fast occurring changes, caused by changes in coupling path length, or as slow occurring changes, caused by workpiece thickness changes. A defect gate forming a part of the test circuit is controlled by adjusting its opening responsive to a change in coupling path length and its closing responsive to a workpiece thickness change.

Abstract: Ultrasonic energy transmission in rectilinear array scanning patterns of soft tissue provides projection density values of the tissue which are recorded as a function of scanning position and angular relationship, .theta., of the subject with a fixed coordinate system. A plurality of rectilinear scan arrays in the same plane for different angular relationships .theta..sub.1 . . . .theta..sub.n thus recorded are superimposed. The superimposition of intensity values thus yields a tomographic image of an internal section of the tissue in the scanning plane.

Abstract: A three-dimensional imaging system for obtaining a three-dimensional image of an object being scanned ultrasonically comprises a source arrangement for sequentially transmitting ultrasonic energy toward the object in successive directions in a first scanning plane, followed by sequential transmission of ultrasonic energy toward the object in successive directions in successive scanning planes parallel to the first scanning plane, a detector arrangement for receiving reflected energy and converting the reflected energy to electrical signals, and a processor for processing the electrical signals to develop reconstructed image data of the object, the reconstructed image data comprising forward projections of the object into a left image plane and a right image plane to form left and right images, respectively, the left and right images forming a stereo pair for composite display by a display unit.